(a) Field of the Invention
This invention relates to seat cushions and the like and more particularly, but not by way of limitation, to a seat cushion used for absorbing shock and isolating vibration when using various types of heavy equipment such as construction vehicles and the like.
(b) Discussion of Prior Art
Heretofore there have been a variety of different types of isolators which have been one-dimensional. By this, the isolators either isolate vibration or absorb shock but not both.
When addressing body related problems due to vibration, an industry term is used called "whole body vibration". This term refers to mechanical energy oscillations, which are transferred to the body as a whole usually through a supporting system such as a seat or platform. Typical exposures to the human body of this type of vibration include automobiles, trucks and operating industrial vehicles. Research has been done to determine the effects of whole body vibration and musculoskeletal disorders such as back pain, sciatic pain, intervertebral disc disorders and herniated disc. The subject invention addresses the above mentioned concerns related to whole body vibration.
In U.S. Pat. No. 5,121,962 to Weber et al., a cushion for absorbing shock and using a piece of visco-elastic material is disclosed. The visco-elastic material is made of a plasticized PVC gel. In U.S. Pat. No. 5,445,858 to Nwoko, an attenuating pad is described for enhancing the capacity for shock absorption. In U.S. Pat. No. 5,749,111 to Pearce, a cushion construction using a gelatinous cushioning media is disclosed. In U.S Pat. No. 5,669,094 to Swanson, a mattress construction is described wherein a layer of visco-elastic foam in combination with latex foam is used.
Also, in U.S. Pat. No. 3,606,463 to Brooks, a seating system is disclosed using a bouncing putty. Further, in U.S. Pat. No. 5,680,662 to Purdy et al. and U.S. Pat. No. 5,737,788 to Castellino et al., a cushioning mattress for reducing shear and friction and a pad for preventing and treating decubitus ulcers are described.
None of the above-mentioned patents incorporate the unique combination of structure and function of the subject ergonomic seat cushion used for both absorbing shock forces and isolating vibration associated with large construction equipment subject to period shock loading and vibration during building construction and similar working conditions.